The National Institute for Occupational Safety and Health issued new nonpowered particulate respirator regulations in 1995. (42 CFR Part 84). A new filter certification system was also developed. The N95 respirator is the most commonly used in industrial and health care environments of the new particulate respirators that have entered the market. The Particulate Respirators of unloaded N95 particulate respirators were compared to the filtration efficiencies of dust/mist (DM) and dust/fume/mist (DFM) respirators certified under the previous regulations (30 CFR Part 11). N95 respirators were found to have higher filtration efficiencies than DM and DFM respirators and noncertified surgical masks in laboratory tests using NaCl certification aerosols and measurements with particle-size spectrometers.
